Following the case, Detective Chief Inspector Claire Wheatley from Northumbria Police’s safeguarding team praised the bravery and courage of the victims to come forward and report the abuse.

She said: “Firstly, I would like to praise the bravery of the victims for coming forward and giving their evidence. It is a testament of their strength and courage as I know this has not been an easy process for them.

“I would also like to recognise the professionalism, dedication and commitment of the officer in charge, DC Julia Robinson, who has worked tirelessly to ensure a thorough investigation during this complex enquiry. Julia was supported by the dedicated multi-agency victim team, which has provided support to the victims throughout this process.

“This was a long and complex investigation and the hard work, dedication and professionalism of all officers involved has helped us to secure today’s convictions and reaffirms our commitment to tackling sexual abuse.

“We know that no sentence will ever take away the pain Sharif has caused his victims but we hope it is some comfort to them to know he has been brought to justice.

“Sharif is a manipulative man who knew what he was doing. He preyed on young, vulnerable women he thought would never report him.

"He thought he was untouchable and he thought he could lie his way out of everything. We are pleased the jury saw though these lies and have found him guilty.

“We all have a role to play in helping tackle these awful crimes which prey on the most vulnerable. I would urge anyone who sees something suspicious to report it to police. This can be done on the 101 number or 999 in an emergency.”

Sharif was found guilty of four charges of rape against three victims and one count of sexual assault. He was also found guilty of:

Three counts of supplying Class A drugs.

One charge of trying to conceal £2,000.

He was found not guilty of:

Two counts of rape against a 17-year-old.

He pleaded guilty to:

Two counts of being concerned in the supply of Class A and B drugs.

Two counts of possession of Class A drugs.

One count of supplying Class A drugs.

Three counts of perverting the course of justice.

One count of perjury.

A number of other people also faced charges as part of Operation Argon, Northumbria Police’s investigation into Sharif’s parties.

Sharif’s brother Amer, 20, of Brunton Terrace, Sunderland, was found guilty of doing acts tending or intending to pervert the course of justice after he helped to try to coerce a woman into making a false statement about one of the victims.

Georgi Karaboykov, 35, of New Pallion Road, Sunderland, was found not guilty of the rape and sexual assault .

Luke Richardson, 21, of Ryhope Street South, Sunderland, was found not guilty of the rape and sexual assault.

Milagros Sanchez, 25, of Chester Road, Sunderland was found not guilty of facilitating sexual exploitation.